PTL 1 discloses an organic electroluminescent device for the purpose of providing an organic EL device or the like that has high external extraction quantum efficiency, a long emission lifetime, and low driving voltage. In the organic electroluminescent device disclosed in this publication, at least two layers A and B in the three or more organic layers provided between the cathode and the anode are formed by coating using nonaqueous solvents. The device includes a mixed region formed between the layer A and the layer B, and the concentration distribution of the constituent component of the layer A or B has a continuous concentration gradient.
PTL 2 discloses a material for organic electronics that can be used to easily form multiple layers by coating, and that can increase the efficiency and the lifetime of an organic EL device, and lower the driving voltage. The material is a mixture containing a first hole transport material and a second hole transport material. The first hole transport material is a polymer or an oligomer having at least one polymerizable substituent and a hole transporting repeating unit within the molecule. The difference in the work functions of the first hole transport material and the second hole transport material is 0.5 eV or less.
PTL 3 discloses an organic electroluminescent device for the purpose of providing an organic EL light-emitting device that has high emission luminance, a few dark spots, and a long lifetime. The organic electroluminescent device disclosed in this publication includes a cathode and an anode on a substrate, and more than one organic layers disposed between the cathode and the anode. At least one of the organic layers is a layer that contains an organic molecule having 10 or less repeating units, and that is obtained by applying and polymerizing a compound having at least one polymerizable group.